A possible concise summary is:
Marvin buys a machine that turns things into gold, but it actually turns them into chocolate with gold wrappers. He pays his house payment with the fake gold, but Goodman finds out and gives him more time. Meanwhile, Jeffy gets inside the machine and becomes a gold statue. Marvin tries to melt him in the oven, but he turns out to be chocolate too. Marvin realizes his mistake and hopes to get the money by next week.
Here are the key facts extracted from the text:
1. Marvin is four months past due on his house payment and owes Goodman $10,000.
2. Marvin buys a machine that turns whatever is put inside it into gold for $101.60 from a loan dolphin.
3. Marvin's son Jeffy crawls into the machine and turns into a gold statue.
4. Marvin pays Goodman with the gold bars made by the machine, but they are actually chocolate with gold wrappers.
5. A dentist breaks into Marvin's house to steal the machine, but he accidentally breaks it and suggests putting Jeffy in the oven to melt the gold.
6. Jeffy comes out of the oven as a normal human covered in chocolate with bits of gold in it.
7. Goodman likes chocolate and gives Marvin until the end of next week to get the money.